title: 'I'll do what they did": social norm information and cancer treatment decisions.
abstract: OBJECTIVE
  Using a cancer-treatment scenario, we tested whether descriptive norm information (e.g., the proportion of other people choosing a particular treatment) would influence people's hypothetical treatment choices.
  
  
  METHODS
  Women from an Internet sample (Study 1 N=2238; Study 2 N=2154) were asked to imagine deciding whether to take adjuvant chemotherapy following breast cancer surgery. Across participants, we varied the stated proportion of women who chose chemotherapy. This descriptive norm information was presented numerically in Study 1 and non-numerically in Study 2.
  
  
  RESULTS
  The descriptive norm information influenced women's decisions, with higher interest in chemotherapy when social norm information suggested that such chemotherapy was popular. Exact statistics about other people's decisions had a greater effect than when norms were described using less precise verbal terms (e.g., "most women").
  
  
  CONCLUSIONS
  Providing patients with information about what other people have done can significantly influence treatment choices, but the power of such descriptive norms depends on their precision.
  
  
  CONCLUSIONS
  Communication of descriptive norms is only helpful if prevailing decisions in the population represent good clinical practice. Strategic presentation of such statistics, when available, may encourage patient outliers to modify their medical decisions in ways that result in improved outcomes.
authors.affiliation: Department of Health Behavior and Health Education, University of Michigan, Ann Arbor, MI 48109-2029, USA. bzikmund@umich.edu
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Zikmund-Fisher
authors.forename: Paul D
authors.initials: PD
authors.lastname: Windschitl
authors.forename: Nicole
authors.initials: N
authors.lastname: Exe
authors.forename: Peter A
authors.initials: PA
authors.lastname: Ubel
mesh_terms: D000328:Adult; D000368:Aged; D001294:Attitude to Health; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000601:surgery; D017024:Chemotherapy, Adjuvant; D016009:Chi-Square Distribution; D003657:Decision Making; D005260:Female; D006801:Humans; D020407:Internet; D008875:Middle Aged; D010379:Peer Group; D012306:Risk